Print blanket washing apparatus



1943- J. H. A. s. M MORDIE ET AL 2,335,782

I PRINT BLANKET WASHING APPAR ATUS I Filed July 26, 1941 5 Sheets-Sheet 1 N0v. 30, 1943. V J. H. A. s. MOMORDIE r AL 2,335,732

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Patented Nov. 30, 1943 PRINT BLANKET WASHING APPARATUS James H. A. S. McMordie, Arlington, and Manson E. Wood, Wakefield, Mass., assignors to Dewey and Almy Chemical Company, North Cambridge, Mass., a corporation of Massachusetts Application July 26, 1941, Serial No. 404,209

Claims.

This invention relates to textil printing blanket washing apparatus, particularly to apparatus used in textile printing machines operated without back grays.

The objects of the invention are to secure a more thorough and complete cleansing ofthe blanket; to prevent dried color from building up on the blanket; to provide an apparatus incapable of creasing, tearing or pinching the blanket; and to provide a washing apparatus .capable of removing all of the color and as much of the' wash water as possible so that the load of water to be evaporated by the dryer may be decreased.

In textile printing, if the use of a back'gray is to be eliminated, itsfunction, which is to'pick up and carry away the surplus color forced through the printed textile, must be performed by the blanket itself. machines, therefore, include a long, endless, waterproof blanket which is washed free of ink and dried before it again is presented at the printing station. As first produced, the blanket had such small ink carryin capacity that the "wash" process was strictly limited to very light patterns. More recently, the surface of the blanket has been modified to give it great ink holding capacity and retentiveness. Blankets now are capable of carrying away all of the color forced through the textile even when blotch patterns are used. None the less, only certain patterns can be printed with complete success; the others still cannot be printed without a back gray, for even if a blanket is able successfully to carry away the surplus ink, the large charge of ink cannot be properly removed by conventional blanket cleansing apparatus.

Color which is left on the blanket turns into a horny mass in the dryer. It does not absorb fresh color, but causes flushing of colors in the design.

Why certain patterns print satisfactorily whi No-back-gray or wash.

has been applied to'the blanket and before it reaches the conventional washer is at least seconds; the temperature of the blanket is about 120-130 F. The time and temperature ar both great enough to permit a change in the dextrine' or other adhesive. These are the reasons why some patterns cannot be printed, for if the dextrine dries to a'continuous film, or if there is too much of it, or even if its surface has hardened somewhat, the conventional-washer cannot get the color off in the time which the printing speeds permit. Hence, color builds up on the blanket.

Essentially, all bodiers or s d in textile printing are lyophilic colloids. These have a common property of swelling in water, but the manner of swelling is best illustrated by joiners fiake glue. In water, the surfaceof the glue becomes slimy at once, but the center remains quite hard for a long time because the swelling of the surface holds back the'penetration of water into the interior layers. We have discovered that this, happens on the blanket as well and no reasonable amount of water will penetrate the entire layer and no reasonable degree of scrubbing will sufiiciently dislodge thecolor left by the patterns which give trouble in the time which is available if conventional practice is followed.

We divide the washing operation between two stations in the run of the blanket. One, we locate as close as possible to the print cylinders, the other remains in its conventional location at the end of the outward run. As the first step, we pick off by adhesion as much color from the blanket as is possible. Immediately after removing a substantial part of the color mechanically, we scrub the blanket with a wet counter-running brush. We also forma pool or sheet of hot water on the blanket and maintain the sheet over the others flush depends upon a surprising number of process happenings which, because of the jobto-Job nature of the finishing business, vary greatly. For example, the specific textile used, tightness of yarn twist, depth and type of engraving, temperature or the blanket, nature of the dye adhesive-whether British, finishers gums, etc., are used, and the way each printer handles his color and sets his rolls, all determine the amount and condition of color left on the blanket.

The speeds of textile printing are high-ranging from 40 to 120 yards a minute and averaging about 80 yards; the time interval after the color whole outward run of the blanket until it reaches the second part of the washing mechanism. Because the brush has loosened the soft color and broken it into clots rather than leaving it as a film, and because, afterwards, the color has hadat least 10 seconds in which to swell in hot water, the first rubber squeeze roll or "cleaner roll of the washer squeezes the colored slime oil and leaves the-blanket practically clean. The blanket then passes over a chisel jet of water which cuts off any remaining surface film and then is squeeze-dried by passing under a second rubber roll and blotted by a felt roller. Because only thoroughly broken-up, softened and dilute color reaches this part of the machine, we are able to pay much more attention to the mechanical reing blanket.

drawings, Figure 1 shows an Details of the printer and dryerare not shown but their respective po sltion is indicated;

Figure 2 is an end view ofthe washer; v

Figure 3 is a section partly in elevation taken on the line 3-8 of Figure 2;

Figure 4 is an end view of the washer apparatus;

Figure 5 is a central section of the same appa ratus; r

Figure 6 is a section partly in elevation of the print end washer taken on the line 6-6 of Figure; and

Figure 7 is a section taken on the line I-'| of Figure 1.

In Figure 1 print end the impression cylinder of the textile printing press is indicated at H). (Color or print rolls are conventional and not shown.) The blanket ll passes over the impression cylinder IO and is properly guided by the rolls l2, 12.

In the return run of the blanket I I, but located as closely to the impression cylinder ID as is practicable yet still avoid interference with the rising web of printed goods, we place a transfer roll [3 against which the wet colored face of the blanket runs. The run of the blanket then continues under the roll I4 and back toward the rear of the machine.

Roll H (see Figures 4 and 6) is connected by the sprockets l5 and J16 and by'the chain il in such a manner that the brush I8 is driven in an opposing direction against the face of the blanket in. All of the color which can be removed by adhesion to another surface is picked off on the solid face of the roll l3 which also, because of its small diameter aids in breaking up the color mass which clings to the face of the blanket. Roll i3 is continuously cleaned by water fed through the drilled pipe l9 and is scraped clean by the doctor blade 2L, iIhe soft color is further broken up and scrubbed by the brush l8 which itself is washed clean by its rotation through the tank 22 of water. It is continuously supplied with fresh water through the drilled pipe 23. Both color scraped ofi by the doctor blade 2| and the wash r water run immediately to waste through the drains 25, 25 (see Figures 4 and 6). The level of water in the tank 22 is controlled by the position of the dam 26. A slide gate 21 allows the water in the tank 22 to be drained when desired.

Enough water is forced through the drilled pipe 23 and into the bite between the brush !8 and the roll M not only to wet the brush but to form a continuous sheet of water on the blanket II which travels with the blanket throughout the whole length of its rearward run. To prevent the water slopping over the margins of the blanket, the blanket boards 24, 24 (Figures 1 and 7) which support the rearward run of the blanket above the drier are shaped in a shallow V form inclining towards the center to maintain the sheet of water over the whole colored portion of the blanket, but leave the margins dry.

Color is never applied to the full face of a print- The unsupported margins of a blanket break away under the printing roll pressure destroying printability. Consequently, two stripes or bands about two inches wide on the face of the blanket adjacent its margins are color free. It is essential that the brush I8 be narrower than dryer end ,blanket where it ultimately builds up to' cause destructive troubles. The proper relationship of brush and blanket is best illustrated in Figure 6.

The axial position of the brush I8 may be adjusted by means of the adjusting screws 28 and 29 to compensate for bristle wear. The drive chain is adjusted by loosening the stud 3| and sliding the slotted bracket 32 which carries the .idler 33 into proper position.

At the rear of the machine the blanket passes over the guide rolls 34, 34 and then drops to loop about the drum 35 of the dryer end washer 36 (see Figure 2). Some of the free falling water which is dumped as the blanketenters its vertical run is intercepted by the splash board 31. Most of it-with its entrained color may be removed if a squeegee is attached to the splash board and bears against the blanket l l.

In that case, fresh water should strike the blanket above the bite and beneath the squeegee, but we find it equallygood practice to allow a consid erable amount of the falling water to drop into the bite between the blanket and the rubber covered cleaner roll 38 where it and the now slimy, swollen, broken-up color paste is squeezed off the blanket and runs down on the inclined deck 39 into the drain sump 4i.

Beneath the cleaner roll'38 and as the blanket progresses further around the drum 35, it is met by a stripping spray 40 of water projected from pipe 30. This removes whatever surface film is left on the blanket and the water is then squeezed off as the blanket passes through the bite between the squeeze 'roll 42 and the drum 35.

Roll 2%) is made of felt to act as a blotter roll which picks off the free moisture on the face of the blanket M. It is stripped by a brass dofling roll 43, the purpose of which not only is to squeeze water from the felt and keep it absorptive, but to strip the rings of water which otherwise form beyond the margins of the blanket on roll 20 and so prevent the back of the blanket from getting wet. Removal of free surface moisture and prevention of back wetting reduces to a materialdegree the evaporation load on the dryer 44.

The type and arrangement of the rolls described above is very-satisfactory when dextrine bodied colors are used. With other bodying substances, however, the print end washer and rolls alone may not remove all of the color. Whenever this is the case we continuethe process of breaking up and mechanically diluting the color begun at the print elid washer at the dryer end by replacing roll 38 by a counterdriven brush. Roll 42 also is replaced by a brush, like- Wise counterdriven, and a second 'spray cleaner corresponding to spray 40 is arranged to strike the blanket at a symmetrical position on the opposite side of the machine.

When brushes are used, we have found it much more satisfactory to use a brush having bristles made of an artificial fibre, for example the one trade-marked Nylon, since the extremely smooth surface on these bristles gives no anchorage for the gum'my color which the brush removes.- Natural bristles generally have not proved as satisfactory asplain rolls.

The water which supplies pipes I9, 23 and 30 shown). tank 45, which is connected to the mill water supply through the ball cock 4!. This is neeessary to prevent fluctuations in the mill supply from changing the pumping rate.

, The structure oi the evaporator dryer i'orms no part of this invention but, essentially, the

blanket travels inwardly in tunnel 41, outwardly in tunnel 48, and in both tunnels is met by a turbulent, hot air blast supplied from ran.

house 4..

livery roll in the dryer end washer assembly it is brought to bear on the blanket by a sprins pressed journal arm, all oi' which are free save for the tension applied by the springs ll to rotateabout their respective. pivots. 'The com-' pression values of the springs are uniform and are calibrated. The respective roll pressures may be adjusted. by setting pointers as shown at Ii, II opposite marked positions on scales as shown at It. By carrying every roll onspring pressed journals. no cutting or pinching or the blanket can take placein the washing apparatus.

Textile inks and colors are no longer exclusively confined to vat and developed col'ors sus-' pended in a water-swelling'gum. Aridye, an emulsion of color particlesand a resinous binder is largely used. Water alone is not effective in removing this dye. Consequently, we have used the word water broadly and in the specification and claims intend it shall mean not only water.

1.1n textile printing blanket washing apparatus comprising a textile printer, a washable ,pl'int blanket. and a .dryer .ior the blanket.-

blanket washingand color diluting means located adjacent the printing station comprising a color transfer roll, means for removing color is furnished by a local pressure pump (not It receives its water from the supply g I 3 2. In textile printing blanket washing apparatus comprising a textile printer, a washable fer'ring a part of the soft color a metallic surrace, breaking up the him or color adhering to the blanket by wet brushing the film, flooding the remaining color with a swelling agent and diluent. maintaining the diluent in contact with;

the color and blanket for an'appreclable time.

and finally removing both diluent and color from g 4. In textile printing blanket washing apps-e ratus comprising a textile printer, a blanket washer and an endless washable print blanket.

having a substantially horizontal flight running toward the washer. means located adjacent the printer in advance oi'said horizontal'ilight' #0 remove, scrub, break up and dilute the him of eolor;applied to the blanket at the printing station, means to maintain a illm of water on the blanket throughout its outward run. and iinal color removing means located adjacent the end.

oi the outward run of the blanket whereby color softened and diluted by; immersion throu out io'r the outward run is-relnoved from the blanket.

blanket trained 'over the printing cylinder and of greater width-than the engraved area of the. printing roll, blanket cleaning means located ad- 40 .iacent the printing cylinder and including a rotary brush substantially. as wide as the engraved area of the printing rollbut of less width. mm the transfer r011. bmmns mean! ii ld 4 than the blanket, whereby spreading of excess or scrubbing the blanket surface and means for supplying and maintaininga sheet oi water on g the outward runoi the blanket.

color beyond the edge offlle blanket is avoided.

' moons. WOOD.

JAMES H. A. S. MGMORJJIE.v 

